HIPPARION. 



201 



Characters. — (Leidy, 1859, p. 105) (1) Crown of the larger specimen, (type, fig. 33) with enamel stained jet black 

 and dentine and cement gray; (2) broken at the bottom and without inner median enamel column [protocone] ; (3) in its 

 present condition two inches in length; (4) moderate degree of internal and posterior curvature. The smaller (para type, 

 fig. 32) brown in color; (5) half worn down; (6) a little less than an inch in length; (7) inner median enamel column [pro- 

 tocone] anteroposterior^ reniform. (Gidley, 1907) (8) One of the smallest and apparently most highly specialized species 

 of the group. (9) Greater elongation of the tooth crowns; (10) very complex plications of the walls of the fossettes; (11) 

 a small, well rounded protocone, differing from that of Hipparion whitneyi and resembling that of II. gracile of Europe. 



ELEPHAS IMPERATOR-EQUUS EXCELSUS ZONE. 18. LATEST PLIOCENE OR EARLIEST PLEISTOCENE. 



Equus princeps Leidy 1890. 

 Text Fig. 166, 166a. 



Hippotherium princeps, Leidy, Joseph. "Hippotherium and Rhinoceros from Florida," Proc. Acad. Nat. Sci. Phila. Vol. XLII, 

 1890 (sig. dated July 29, 1890), pp. 182-183, text fig. p. 182. 



Hipparion princeps Leidy 1890, = Equus ffraternus Leidy, and. Gidley, 1918. 



Fig. 166. Type of Hipparion princeps Leidy (= Equus ffraternus Leidy), U. S. Nat. Mus. 3299. (Left) Original figure 

 of the type, after Leidy, 1890, p. 182. (Three right-hand figures) Type tooth redrawn under the direction of Osborn by S. 

 Oka; crown, external and anterior views. Natural size. 



Horizon and locality. — (Leidy) Peace Creek, De Soto County, Florida, Peace Creek formation of late Pliocene or 

 early Pleistocene age. Type collected by Joseph Willcox and Wm. M. Meigs, from the phosphate bed of T. S. Morehead. 

 These phosphate beds contain also Equus, Elephas, and Gh/ptotherium. 



Type. — U. S. Nat. Mus. 3299. (Leidy, Gidley) A premolar, p 3 or p\ of the right side. Measurements : (Leidy) 



H. ingenuum H. plicatile II. princeps 

 Fore and aft diameter .019 .020 .032 

 Transverse .017 .024 .031 

 Height of crown 043+ .030+ .075 + 



